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❄️ Heat Pump & HVAC Thermal Load · EN 12831 & ACCA Manual J Reference

Heat Pump Sizing for 484 m² (5,210 sq ft) — UK & Temperate Maritime (-5°C Design, UK/IE/NZ)

Thermal heat loss calculation, recommended heat pump capacity (kW, BTU/h & HVAC Tons), SCOP efficiency, and annual electricity consumption.

Recommended Heat Pump25.9 kW88,374 BTU/h (7.36 Tons)
Annual Electricity Usage11,090 kWh/yrDelivers 45,468 kWh Heat (SCOP 4.1)
Savings vs Direct Electric34,378 kWh/yrSpecific Load: 52.2 W/m²
Electrical Circuit (230V)45 A BreakerPeak Compressor Input: 7.85 kW

Thermal & Electrical Specification Table (484 m² / 5,210 sq ft)

Heated Floor Area484 m² (5,210 sq ft)
Climate Zone & Design Outdoor TempUK & Temperate Maritime (-5°C Design, UK/IE/NZ)
Building Insulation EnvelopeStandard Double-Glazed Insulation (55 W/m² Base) (52.2 W/m² Peak)
Peak Space Heating Load25.26 kW Thermal
Recommended Heat Pump Output (Incl. DHW)25.9 kW (88,374 BTU/h · 7.36 Tons)
Seasonal Coefficient of Performance (SCOP)4.1 (340%–450% Seasonal Efficiency)
Annual Heat Demand vs Electricity Consumed45,468 kWh Heat → 11,090 kWh Electricity

Frequently Asked Questions

What kW size heat pump do I need for a 484 m² (5210 sq ft) house?

For a 484 m² (5210 sq ft) building with Standard Double-Glazed Insulation (55 W/m² Base) in UK & Temperate Maritime (-5°C Design, UK/IE/NZ), the peak space heating load is 25.26 kW (52.2 W/m²). Including domestic hot water allowance, a 25.9 kW (88,374 BTU/h / 7.36 Ton) heat pump is recommended.

How many kWh of electricity does a 25.9 kW heat pump use per year?

With a Seasonal Coefficient of Performance (SCOP) of 4.1 over 1800 full-load equivalent heating hours, the heat pump consumes approximately 11,090 kWh of electricity per year to deliver 45,468 kWh of heat — saving 34,378 kWh/year compared to direct electric radiators.